The bacterium Bacillus thuringiensis is widely used in contemporary biology as a/an

  • Indicator of water pollution

  • insecticide

  • agent for the production of dairy products

  • agent for the production of dairy products


B.

insecticide

Bacillus thuringiensis is Gram-positive, soil dwelling bacterium also occurs naturally in the gut of caterpillars of various types of moths and butterflies.

During sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal

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Point mutation involves

  • insertion

  • change in the single base pair

  • duplication

  • duplication


B.

change in the single base pair

The point mutations involve alterations in the structure of gene by altering the structure of DNA. Point mutations are of two types- (i) base pair substitution and (ii) Frameshift substitution.
Insertion is the addition of one of more nitrogenous bases to a nucleotide chain.
Duplication is the presence of one block of genes more than once in the haploid component.
Deletion is the removal of one or more nitrogenous bases from a nucleotide chain.

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Which one of the following is commonly used in the transfer of foreign DNA into crops plants?

  • Trichoderma hazianum

  • Meloidogyne incognita

  • Agrobacterium tumefaciens

  • Agrobacterium tumefaciens


C.

Agrobacterium tumefaciens

The uptake of foreign DNA or transgenes by plant cells is called transformation. A variety of techniques have been used to introduce transgenes into plant cells, these can be grouped into the following two categories0 (i) Agrobacterium-mediated and (ii) direct gene transfers.
Agrobacterium tumefaciens mediated transformation eliminates the need for regeneration from tissue explants.

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Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the character.

  • The female parent is heterozygous

  • The parents could not have a had a normal daughter for this character

  • The trait under study could not be colour blindness

  • The trait under study could not be colour blindness


A.

The female parent is heterozygous

The given pedigree chart shows that both the daughters received the gene from the parents, while son may be normal or affected. It shows that the female parent is heterozygous.

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Which one of the following condition in humans is correctly matched with tis chromosomal abnormality /linkage?

  • Klinefelter's syndrom-44 autosomes + XXX

  • Colourblindness- Y-linked

  • Erythroblastosis foetails - X-linked

  • Erythroblastosis foetails - X-linked


A.

Klinefelter's syndrom-44 autosomes + XXX

Klinefelter's syndrome si represented by 44 autosome+ XXY. When an abnormal egg with XX chromosome is fertilised by a sperm carrying Y-chromosome a zygote having XXY sex chromosomes is formed. The resulting young one is an abnormal sterile male. 

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